1. APES Unit 3 – Energy Lesson 1 – Energy Basics

2. Learning Targets – Unit 3 Lesson 1 What is energy? Differences between kinetic and potential energy Differences between renewable and nonrenewable energy Review of photosynthesis & cellular respiration First & Second Laws of Thermodynamics

3. Energy is a fundamental component of environmental systems

4. What is energy? The capacity of a physical system to do work, or transfer heat. All living systems absorb energy from their surroundings and use it to organize and reorganize molecules within their cells to power movement. – Water flowing into a lake has energy because it moves and can move objects in its path. – Plants absorb solar energy and use it in photosynthesis.

5. We use a variety of energy sources We use these energy sources in our… Homes Machinery – industrial, farm, Vehicles – cars, trucks, trains, planes, ships, etc. Offices – heat, light, A/C Most of our energy comes from ____ This leads to – Solar radiation – Photosynthesis – Fossil fuels (highly combustible substances formed from the remains of organisms) Key point: Fossil fuels are really solar energy.

6. The Sun emits electromagnetic radiation This is a form of energy that includes, but is not limited to, visible light, ultraviolet light, and infrared energy, which we perceive as heat.

7. Forms of Energy The basic unit of energy in the metric system is the joule (J) A joule is the amount of energy used when a 1- watt light bulb is turned on for 1 second. Other energy units are commonly used, such as calories (amt. of energy to heat 1 g of water 1 o, Calories (food), Btu (British thermal units), and kilowatt-hours (kWh).

8. Energy and Power Energy and power are NOT the same thing, even though we use the words interchangeably. Energy is the ability to do work, whereas Power is the rate at which work is done Energy = power x time Power = energy / time

9. Potential and Kinetic Energy What is the difference?

10. Potential and Kinetic Energy Potential energy: energy that is stored but has not yet been released (ex. water behind a dam) Kinetic energy: energy of motion (ex. water flowing past the dam, downstream. This kinetic energy can be captured and transferred to a turbine and generator to ultimately be used as electrical energy.)

11. Potential and Kinetic Energy Systems contain potential energy, kinetic energy, or some of each. Potential energy stored in chemical bonds is known as chemical energy. – Ex. the energy in food. By breaking down the high- energy bonds in the pizza you had for lunch, your body obtains energy to power its activities and functions. – An automobile engine combusts gasoline and releases it as chemical energy to propel the car.

12. Temperature All matter, even the frozen water in the world’s ice caps, contains some energy. When we say energy moves matter, we mean it is moving the molecules within a substance. The measure of the average kinetic energy of a substance is its temperature. Changes in temperature, and therefore in energy, can convert matter from one state to another.

13. The First and Second Laws of Thermodynamics

14. The First Law of Thermodynamics Energy is neither created nor destroyed. Like matter, energy changes form. You can’t get something for nothing. – Ex. When an organism needs biologically usable energy, it must convert it from an energy source such as the Sun or food. It may sometimes be difficult to identify where energy is going, but it is always conserved.

15. First Law of Thermodynamics Conservation of energy within a system. In a car, the potential energy of gasoline is converted into other forms of energy. Some of that energy leaves the system, but all of it is conserved.

16. The Second Law of Thermodynamics When energy is transformed, the quantity of energy remains the same, but its ability to do work diminishes.

17. The Second Law of Thermodynamics Also focuses on the fact that all systems move toward randomness rather than towards order = entropy Entropy is always increasing in a system unless new energy from outside the system is added to create order. – Ex. your bedroom w/o you putting energy into it to clean/organize it. – Energy flows from hot to cold (Water won’t boil w/o input of energy, but hot water will cool as its energy dissipates into the surrounding air  important in many of the global circulation patterns that are powered by the energy of the Sun

18. Energy Efficiency The ratio of the amount of work that is done to the total amount of energy that is introduced into the system in the first place. (a) The energy efficiency of a traditional fireplace is low because so much heated air can escape through the chimney. (b) A modern woodstove, which can heat a room using much less wood, is much more energy efficient.

19. Energy Efficiency Example A modern coal-burning power plant can convert 1 metric ton of coal,containing 24,000 megajoules (MJ; 1 MJ = 1 million joules) of chemical energy into about 8,400 MJ of electricity. Since 8,400 is 35 percent of 24,000, this means that the process of turning coal into electricity is about 35 percent efficient. The rest of the energy from the coal—65 percent—is lost as waste heat.

20. Energy Efficiency Example cont. In the electrical transmission lines between the power plant and the house, 10 percent of the electrical energy from the plant is lost as heat and sound, so the transport of energy away from the plant is about 90 percent efficient.

21. Energy Efficiency Example cont. Finally, we know that the conversion of electrical energy into light in an incandescent bulb is 5 percent efficient; again, the rest of the energy is lost as heat. To calculate the energy efficiency of converting coal into incandescent lighting by multiplying all the individual efficiencies:

22. Energy Quality The ease with which an energy source can be used for work – Ex. gasoline is a high-quality energy source because its chemical energy is concentrated and because we have technology that can conveniently transport it from one location to another. In addition, it is relatively easy to convert gasoline energy into work and heat. – On the other hand, wood is a lower-quality energy source. It has half the energy concentration of gasoline and is more difficult to use to do work. Energy quality is one important factor humans must consider when making energy choices.

23. What is the difference between power and energy? Why is it important to know the difference between power and energy? How do potential energy and kinetic energy differ? What is chemical energy? What are the first and second laws of thermodynamics?

24. Energy conversions underlie all ecological processes Life requires order. If organisms were not made up of molecules organized into structures such as proteins and cells, they could not grow—in fact, they could never develop in the first place. All living things work against entropy by using energy to maintain order. The form and amount of energy available in an environment determines what kinds of organisms can live there.

25. Which of these pictures represents the location with the most available energy?

26. Photosynthesis Cellular Respiration Photosynthesis & Cellular Respiration How Energy Flows through an Ecosystem

27. What do you remember about Photosynthesis and Cellular Respiration? What performs each process? Purpose of each process? What are the reactants & products?

30. Photosynthesis & Cellular Respiration All organisms— including producers —carry out respiration to fuel their own metabolism and growth. Producers generate moreO 2 via photosynthesis than they consume via respiration (net production of O 2 ) Producers only respire, consuming O 2 without generating it, yet producers photosynthesize more than they respire. Net effect is an excess of oxygen that is released into the air and an excess of carbon that is stored in the tissues of producers.

31. Ecosystem Productivity Ecosystem Productivity – Understanding Trophic Levels, Food Chains and Food Webs We already studied the transfer of energy through trophic levels in Unit 2. The amount of energy available in the ecosystem determines how much life the ecosystem can support. To understand how ecosystems function, or how to manage and protect them, we must understand where the energy in an ecosystem comes from.

32. Ecosystem Productivity Environmental scientists look at the total amount of solar energy that the producers in an ecosystem capture via photosynthesis over a given amount of time = gross primary productivity (GPP) of the ecosystem. Note that the term gross, as used here, indicates the total amount of energy captured by producers. Energy captured - the energy respired by producers = ecosystem’s net primary productivity (NPP): NPP = GPP − respiration by producers Ex. Think paycheck.

33. Ecosystem Productivity GPP is essentially a measure of how much photosynthesis is occurring over some amount of time. Unfortunately converting sunlight into chemical energy is not an efficient process.

34. NPP Varies Among Ecosystems

35. Provide an example of how organisms convert energy from one form into another. Why is photosynthesis an important process? What determines the productivity of an ecosystem? How efficiently is energy transferred between trophic levels in an ecosystem?

36. Scale of Global Energy Is Enormous Drives 500,000 cars; using over 500,000 gallons of petroleum every day OECD population equals 1,200 such cities today -Growing to almost 1,300 by 2030 Consumes over 1,000 gallons of oil per minuteRequires two dedicated, world-scale power plantsNeeds 6 Million BTUs of energy every secondUses 150 tons of coal each hour On average, an city of 1 million people: Today the world uses 15 billion BTUs of energy every second

37. Developed nations consume lots of energy Developing nations use manual or animal energy instead of fossil fuels Developed Transportation Industry Other Developing Subsistence Activities (agriculture, food preparation, home heating)

38. 2005 – 2030 Growing Global Demand By Sector Quadrillion BTUs 2005 2030 Transportation Industrial Res/Comm PowerGen Energy Savings

39. With this much demand, what sources are there to meet the need? Renewable vs. Non-renewable Energy Sources

40. Renewable & Nonrenewable Resources Renewable energy = supplies of energy will not be depleted by our use – Ex. Sunlight, geothermal energy, and tidal energy Nonrenewable energy at our current rates of consumption we will use up Earth’s accessible store of these sources in a matter of decades to centuries – Oil, coal, natural gas, nuclear energy – To replenish the fossil fuels we have depleted so far would take millions of years

41. Renewable vs. Nonrenewable Energy

42. Fossil fuels are created from fossils Fossil fuels we burn today were formed from the tissues of organisms that lived 100-500 million years ago Came from organic material is broken down in an anaerobic environment = one that has little or no oxygen – Bottoms of deep lakes, swamps, and shallow seas Types of Fossil Fuels: Organic matter is eventually converted into coal, crude oil or natural gas.

43. Fossil fuels are our dominant source of energy high-energy content of fossil fuels efficient to burn, ship, and store replaced biomass generate electricity a secondary form of energy that is easier to transfer and apply to a variety of uses

44. Learning Targets – So can you…? Define energy and power? Identify differences between kinetic and potential energy and chemical? Explain why energy efficiency is important? State the importance of photosynthesis & cellular respiration? Explain the First & Second Laws of Thermodynamics? Explain how NPP determines the ecosystem’s capacity? Identify differences between renewable and nonrenewable energy?

45. Practice Questions 1.The capacity to do work is called ____. a. kinetic energyb. potential energy c. mechanical energyd. energy 2. The best definition of heat is ____. a. potential energyb. temperature c. transfer of energyd. kinetic energy

46. Practice Questions 3. The conclusion that it is impossible to completely convert heat into work without making other changes in the universe is ___. a. the first law of thermodynamics b. the second law of thermodynamics 2. A Watt is ____. a. 1 s/Jb. 1 J/s c. 1 cal/s d. 1 s/cal

47. Practice Questions 5. A car ad claims there is a new mechanical part of the engine that allows for 100% recovery of the energy used during burning gasoline. You should be skeptical of such claims because they violate the ___. a. first law of thermodynamics b. second law of thermodynamics c. law of conservation of matter d. activation energy for all chemical reactions